Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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METHOD FOR SMELTING NON-FERROUS METAL SULFIDES IN A
SUSPENSION SMELTING FURNACE AND SUSPENSION SMELTING
FURNACE
Field of the invention
The invention relates to a method for smelting non-ferrous metal sulfides in a
suspension
smelting furnace and a suspension smelting furnace.
The invention relates to a method that takes place in the suspension smelting
furnace,
such as a flash smelting furnace or a flash converting furnace, and to a
suspension smelting
furnace, such as a flash smelting furnace or a flash converting furnace.
Publication WO 2007/113375 relates to a method for treating solids-containing
process gas
in a suspension smelting furnace, comprising directing the process gas from
the reaction shaft of
the suspension smelting furnace to a settler and, further, through a raised
shaft to a waste heat
boiler to cool the process gas, whereby, through one or more gas nozzles
placed on the settler top
wall, oxidizing gas is fed into the process gas flowing in the settler,
whereby the amount of
oxidizing gas is adjusted during the process so that the amount of sulfides
contained in the solid
matter of the process gas that is directed to the waste heat boiler is
minimized. Publication WO
2007/113375 relates also to equipment for treating solids-containing process
gas in a suspension
smelting furnace, wherein the process gas is directed from the reaction shaft
of the suspension
smelting furnace to the settler and, further, through the raised shaft to the
waste heat boiler to
cool the process gas. One or more gas nozzles are arranged on the top wall of
the settler for
feeding oxidizing gas into the process gas flowing in the settler, whereby the
amount of
oxidizing gas can be adjusted during the process so that the amount of
sulfides contained in the
solid matter of the process gas that is directed to the waste heat boiler is
minimized.
Publication WO 00/70103 relates to a method and equipment, whereby matte with
a high
non-ferrous metal content and disposable slag are produced simultaneously in a
suspension-
smelting furnace from non-ferrous sulfide concentrate. According to the
invention, a
carbonaceous reducing agent is charged to the settler of a suspension smelting
furnace via
tuyeres to the part of the furnace which has a reduced cross-sectional area.
Objective of the invention
The object of the invention is to provide a method for smelting non-ferrous
metal
sulfides in a suspension smelting furnace and suspension smelting furnace
having
improved blending of fluid and/or pulverous matter into process gases which
are created
in the reaction space of the suspension smelting furnace.
Short description of the invention
The invention is based on arranging injection means for injecting at least one
of fluid, such
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as liquid, for example small water droplets, and/or gas, for example technical
oxygen, and pulverous
matter, for example coal or coke powder, into the settler from at least one of
the side wall structure
of the settler so that at least one of fluid and pulverous matter is injected
into the settler above the
top surface of the layer of melt in the settler. By arranging injection means
in this manner, fluid
and/or pulverous matter fed by means of the injection means will be fed into
the process gases in the
settler and not into the melt in the settler with the result that the
composition of the melt would be
changed.
The invention can be used for different purposes in a suspension smelting
furnace. The
intended use depends on the furnace geometry, type of raw material to be
smelted in the
suspension smelting furnace and type of off-gas line i.e. type of system for
processing process
gases formed in the suspension smelting process after exiting the uptake shaft
of the suspension
smelting furnace.
One purpose is to oxidize residual sulfide particles in the dust created in
the reaction shaft of
the suspension smelting furnace into oxidic particles in order to easier
create sulphate particles
further down in the off-gas line.
Another purpose is to lower the temperature of the process gases which are
created in the
suspension smelting furnace and which are removed from the suspension smelting
furnace via the
uptake shaft.
Another purpose is to amend the composition of the particles in the process
gases which are
created in the suspension smelting furnace so that the particles, if and when,
they stick to the inner
walls of the settler or to the inner walls of the uptake shaft of the
suspension smelting furnace and
create build-up, the build-ups has a lower melting point compared to build-ups
solely composed of
particles in the process gases, i.e. melt away the buildup,.
Another purpose is to amend the composition of the particles in the process
gases which are
created in the suspension smelting furnace and the same time lower the
temperature of the process
gas so that the particles are in solid form in the gas phase temperature,
which minimizes the sticking
of the particles to the sidewalls of the uptake shaft.
List of figures
In the following the invention will described in more detail by referring to
the figures,
which
Figure 1 is a principle drawing of a suspension smelting furnace according to
a preferred
embodiment of the invention, and
Figure 2 shows the suspension smelting furnace shown in figure 1 as cut along
line A-A in
figure 1.
Detailed description of the invention
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The invention relates to a method for smelting non-ferrous metal sulfides in a
suspension
smelting furnace and to a suspension smelting furnace.
The figures shows an example of a suspension smelting furnace according to a
preferred
embodiment of the invention
First the method for smelting non-ferrous metal sulfides such as sulfidic
copper concentrate,
sulfidic nickel concentrate, sulfidic zinc concentrate, or sulfidic matte, for
example sulfidic copper
matte, sulfidic nickel matte, or sulfidic zinc matte, in a suspension smelting
furnace will be
described in greater detail.
The method includes using a suspension smelting furnace comprising a reaction
shaft I, a
settler 2 in communication with the reaction shaft 1 via a first communication
point 3 that is formed
between a lower end of the reaction shaft 1 and the settler 2, and an uptake
shaft 4 in
communication with the settler 2 via a second communication point 5 that is
formed between the
settler 2 and a lower end of the uptake shaft 4. The settler 2 comprises a
bottom structure 6, a top
wall structure 7, a first side wall structure 8 and a second side wall
structure 9 between the bottom
structure 6 and the top wall structure 7, and a first end wall structure 10 at
one end of the settler 2
and a second end structure 11 at the opposite end of the settler 2.
The method included a feeding step for feeding by means of a concentrate
burner 12 non-
ferrous metal sulfides 13 and reaction gas 14 such as air, oxygen-enriched air
or oxygen and
possible also flux and/or fine dust into the reaction shaft 1 to have non-
ferrous metal sulfides 13 and
reaction gas 14 react together in the reaction shaft I to produce melt (not
shown or marked with a
reference numeral).
The method includes also a collecting step for collecting melt from the
reaction shaft 1 in
the settler 2 so that a layer of melt 15 having a top surface 16 is be formed
in the settler 2.
The method includes also a gas removing step for removing process gases 17
from the
suspension smelting furnace via the uptake shaft 4.
The method includes additionally an arranging step for arranging at least one
injection
means 18 for injecting at least one of fluid 19, such as liquid for example
small water droplets
and/or gas for example technical oxygen, and pulverous matter 20 for example
pulverized coal or
coke into the settler 2 from at least one of the first side wall structure 8
and the second side wall
structure 9 of the settler 2, so that at least one of fluid 19 and pulverous
matter 20 injected into the
settler 2 by means of said at least one injection means 8 will enter the
settler 2 above the top surface
16 of the layer of melt 15 in the settler 2.
The method includes additionally an injecting step for injecting at least one
of fluid 19 and
pulverous matter 20 into the settler 2 by means of said at least one injection
means 18.
In a preferred embodiment of the method the injecting step includes injecting
at least
one of fluid 19 and pulverous matter 20 into the settler 2 by means of at
least one injection means
18 a direction parallel or almost or substantially parallel with the top
surface 16 of the layer of melt
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15. By doing so, mixing of fluid 19 and/or pulverous matter 20 fed by means of
said at least one
injection means 18 with the layer of melt 15 in the settler 2 can more
effectively be avoided,
because the risk that a jet containing fluid 19 and/or pulverous matter 20
hits the top surface of the
layer of melt 15 is in this embodiment reduced.
In another preferred embodiment of the method the injecting step constitutes
of injecting
at least one of fluid 19 and pulverous matter 20 into the settler 2 by means
of at least one injection
means 18 a direction parallel with the top surface 16 of the layer of melt 15.
In a preferred embodiment of the method the arranging step includes arranging
injection
means 18 at both the first side wall structure 8 of the settler 2 and the
second side wall structure 9 of
the settler 2. In this preferred embodiment of the method, the arranging step
included preferably,
but not necessarily, arranging the injection means 18 in the arranging step in
an unaligned
configuration so that the injection means 18 at the first side wall structure
8 points at the opposite
second side wall structure 9 and so that the injection means 18 at the second
side wall structure 9
points at the opposite first side wall structure 8 as is shown in figure 2. In
other words, in this
preferred embodiment of the method, the arranging step included preferably,
but not
necessarily, arranging the injection means 18 in the arranging step so that
the injection means 18
are not aligned in such manner that the injection means 18 at the first side
wall structure 8 would
points at the injection means 18 at the opposite second side wall structure 9
and vice versa. By
arranging the injection means 18 in such unaligned configuration, the
possibility that fluid 19 and/or
pulverous matter 20 injected by means of injection means 18 at the first side
wall structure 8 will
collide in the middle of the settler 2 with fluid 19 and/or pulverous injected
by means of injection
means 18 from the opposite second side wall structure 9 is lower, and this
leads to an evener
distribution of fluid 19 and/or pulverous matter 20 injected by means of
injection means 18 in the
settler 2.
In a preferred embodiment of the method the arranging step includes arranging
at least one
injection means 18 at a region of the settler 2 between the first
communication point 3 that is
formed between the lower end of the reaction shaft 1 and the settler 2 and the
second
communication point 5 between the settler 2 and a lower end of the uptake
shaft 4.
In a preferred embodiment of the method fluid 19 and/or pulverous matter 20 is
in the
injecting step injected into the settler 2 by means of said at least one
injection means 18 above the
top surface 16 of the layer of melt 15 in the settler 2.
In a preferred embodiment of the method fluid 19 and/or pulverous matter 20 is
in the
injecting step injected into the settler 2 by means of said at least one
injection means 18 into process
gases 17 present in the settler 2 above the top surface 16 of the layer of
melt 15 in the settler 2.
Next the suspension smelting furnace will be described in greater detail.
The suspension smelting furnace comprises a reaction shaft 1.
The suspension smelting furnace comprises additionally a concentrate burner 12
for
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feeding non-ferrous metal sulfides 13 such as sulfidic copper concentrate,
sulfidic nickel
concentrate, sulfidic zinc concentrate or sulfidic matte, for example sulfidic
copper matte, sulfidic
nickel matte, or sulfidic zinc matte, and reaction gas 14 such as air, oxygen-
enriched air or oxygen
and possible also flux and/or fine dust into the reaction shaft I to have non-
ferrous metal sulfides 13
5 and reaction gas 14 react together in the reaction shaft 1 to produce
melt.
The suspension smelting furnace comprises additionally a settler 2 in
communication
with the reaction shaft 1 via a first communication point 3 that is formed
between a lower end of the
reaction shaft 1 and the settler 2, wherein the settler 2 is adapted for
receiving melt from the reaction
shaft 1 so that a layer of melt 15 having a top surface 16 is formed in the
settler 2. The settler 2
to comprises a bottom structure 6, a top wall structure 7, a first side
wall structure 8 and a second side
wall structure 9 between the bottom structure 6 and the top wall structure 7,
and a first end wall
structure 10 at one end of the settler 2 and a second end structure 11 at the
opposite end of the settler
2.
The suspension smelting furnace comprises additionally an uptake shaft 4 for
removing
process gases 17 from the suspension smelting furnace via the uptake. The
uptake shaft 4 in
communication with the settler 2 via a second communication point 5 that is
formed between the
settler 2 and a lower end of the uptake shaft 4.
The suspension smelting furnace comprises additionally at least one injection
means 18
for injecting at least one of fluid 19, such as liquid, for example small
water droplets, and/or gas, for
example technical oxygen, and pulverous matter 20, for example pulverized coal
or coke, into the
settler 2 from at least one of the first side wall structure 8 and the second
side wall structure 9 of the
settler 2, so that at least one of fluid 19 and pulverous matter 20 is
injected by means of said least
one injection means 18 into the settler 2 above the top surface 16 of the
layer of melt 15 in the
settler 2.
In a preferred embodiment of the suspension smelting furnace, said at least
one injection
means 18 for injecting fluid 19 and/or pulverous matter 20 into the settler 2
is configured for
injecting fluid 19 and/or pulverous matter 20 into the settler 2 in a
direction parallel or almost or
substantially parallel with the top surface 16 of the layer of melt 15.
In a preferred embodiment of the suspension smelting furnace, injection means
18 are
arranged at both the first side wall structure 8 of the settler 2 and the
second side wall structure 9 of
the settler 2. In this preferred embodiment of the suspension smelting
furnace, the injection
means 18 are preferably, but not necessarily, arranged in an unaligned
configuration so that the
injection means 18 at the first side wall structure 8 points at the opposite
second side wall structure
9 and so that the injection means 18 at the second side wall structure 9
points at the opposite first
side wall structure 8 as is shown in figure 2. In other words, in this
preferred embodiment of the
suspension smelting furnace, the injection means 18 are preferably, but not
necessarily,
arranged so that the injection means 18 are not aligned in such manner that
the injection means 18 at
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the first side wall structure 8 would point at the injection means 18 at the
opposite second side wall
structure 9 and vice versa. By arranging the injection means 18 in such
unaligned configuration, the
possibility that fluid 19 and/or pulverous matter 20 injected by means of
injection means 18 from
one side wall structure 8 will collide in the middle of the settler 2 with
fluid 19 and/or pulverous
matter 20 injected by means of injection means 18 from the opposite second
side wall structure 9 is
lower, which leads to an evener distribution of fluid 19 and/or pulverous
injected by means of
injection means 18 into the settler 2.
In a preferred embodiment of the suspension smelting furnace at least one
injection
means 18 is arranged in a region of the settler 2 between the first
communication point 3 that is
formed between the lower end of the reaction shaft 1 and the settler 2 and the
second
communication point 5 that is formed between the settler 2 and the lower end
of the uptake shaft 4.
It is apparent to a person skilled in the art that as technology advances, the
basic idea of
the invention can be implemented in various ways. The invention and its
embodiments are
therefore not restricted to the above examples, but they may vary within the
scope of the claims.
